Electrostatic charge control for in-tank fuel module components

ABSTRACT

A grounding arrangement for an in-tank fuel system includes a fuel level sensor assembly of a fuel module comprising a conductive card body and a resister card supported on the conductive card body. The resister card includes a conductive trace in conductive contact with the conductive card body. The card body is conductively connected to a conductive fuel module component. The trace is adapted to be connected to the ground plane of a vehicle. Other traces on the resister card are in the electrical circuit of the fuel level sensor assembly. The fuel module further includes a conductive blade having a knife edge and in conductive contact with a conductive fuel module component. The knife edge cuts through the insulation of an insulated conductor to allow the knife edge to be in contact with the conductive element of the conductor.

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/120,554, filed on May 3, 2005, and also claims the benefitsunder Title 35 USC § 120 based on U.S. Provisional Application No.60/668,313, filed on Apr. 5, 2005.

BACKGROUND OF THE INVENTION

Pending application for U.S. patent Ser. No. 10/441,213 disclosesstructure for providing an electrostatic discharge path to ground ofvarious components within a vehicular in-tank fuel module.

The present invention similarly relates to in-tank fuel modules havingcomponents made of plastic or polymeric materials. More specifically, itrelates to in-tank fuel modules arranged to prevent the accumulation ofand provide for the safe dissipation of electrostatic charges that mightbe generated as a result of fuel flow.

The in-tank fuel module for a fuel tank of a vehicle or other deviceemploying an internal combustion engine typically includes a pluralityof separate components, such as a reservoir, a fuel pump and motor, fuelfilter and housing, a pressure regulator and housing, an aspiration jetpump and the like. It can happen that such components are made ofnon-conductive materials or may include elements that are electricallyconductive; but, the electrically conductive element is electricallyinsulated from the associated electrical circuit that defines a groundplane. For instance, the conductive component may be disposed within ormounted on a non-conductive body, that is, a component that lackssufficient conductivity to create a path to dissipate an electrostaticcharge.

Conductive, as well as non-conductive components of an in-tank fuelmodule are susceptible of accumulating an electrostatic charge. It iswell known to employ an arrangement that provides for dissipation ofsuch static charge to prevent excessive build-up. Various examples aredescribed in U.S. Pat. Nos. 5,076,920; 5,647,330; 5,785,032; 6,047,685;6,206,035 and 6,435,163.

As the investigation of electrostatic charge build-up in in-tank fuelmodules proceeds, refinements in the overall scheme for protectionevolve. The present invention results from this process. Not only doesit recognize the advantage to be derived from implementing suchprotection in areas not previously considered significant, it alsoprovides enhanced mechanisms for accomplishing an overall improvement inthe protection afforded.

To control build-up of the electrostatic charge in the components of anin-tank fuel module, it is known in the art to electrically connect thecomponent to the vehicle ground plane, usually to the negative terminalof the battery that defines that electrical plane. It is known to usemetal wires to electrically connect the components to the ground, or toother grounded conductive components that are connected to the vehicleground plane. It is contemplated by this invention to provide newarrangements for providing such a ground path.

The fuel level sensor detects the fuel level in a fuel tank, usuallythrough a float and pivotal arm physically located in or on the in-tankfuel module. An electric circuit having a variable resistance card isused. A movable cross bar or contact member coacts with the resistercard to alter the circuit characteristics to change the reading on afuel gauge. This circuit includes an electrical path that is extantwithin the module and is ultimately connected to the ground plane. Itprovides a previously unrecognized path for electrostatic chargedissipation.

Moreover, the fuel level sensor assembly usually includes a metallicfloat arm Since the float arm is formed of a metallic material, thefloat arm is susceptible of collecting electrostatic charge. However,since the wiper retainer and the base are formed of a non-conductiveplastic, any electrostatic charge collected in the metallic arm isunable to dissipate to the circuit ground plane. Connection of themetallic float arm to a conductor of the level sensor circuit residentin the module is a solution to both the problem of undesirableelectrostatic accumulation and provision of an effective electrostaticcharge dissipation path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view, partially in cross section, and partially brokenaway, of an in-tank fuel module illustrating various principles of thepresent invention.

FIG. 2 is a partially broken away front view of another type of in-tankfuel module illustrating details of an embodiment of the presentinvention.

FIG. 3 is a perspective view of the top or exterior of the flange of thefuel module of FIG. 2.

FIG. 4 is a perspective view of the under side or inner surface of theflange of FIG. 3.

FIG. 5 is a front view of a fuel level sensor assembly incorporatingprinciples in accordance with the present invention.

FIG. 6 is a top view of the fuel sensor assembly of FIG. 5.

FIG. 7 is a sectional side view of a contact member of the fuel levelsensor assembly of FIG. 5.

FIG. 8 is a front view of a contact member element of the fuel levelsensor assembly of FIG. 5.

FIG. 9 is a sectional view of the contact carrier element of the fuelsensor of FIG. 5.

FIG. 10 is a front view of the contact carrier element of the fuel levelsensor assembly of FIG. 5.

FIG. 11 is a sectional view of the contact carrier, the float arm, andthe contact member of the fuel level sensor of FIG. 5 with a conductivefinger formed on the contact member that contacts the float arm.

FIG. 12 is a sectional view of an alternate embodiment that provides forelectrostatic charge dissipation from a float arm to the resistor cardbody.

FIG. 13 is a front view of a dissipation cap of the embodiment of FIG.12.

FIG. 14 is a modified form of a dissipation cap for the embodiment ofFIG. 12.

FIG. 15 is a plan view of a fuel level sensor illustrating arrangementsfor dissipation of electrostatic charges.

FIG. 16 is a perspective view of a fuel level sensor illustratingarrangements for dissipation of electrostatic charges.

FIG. 17 is a plan view of a conductive connection blade of the fuellevel sensor of FIG. 16.

FIG. 18 is a bottom view of the conductive connection blade of FIG. 17.

FIG. 19 is a fragmentary view partially in section of a portion of theapparatus of FIG. 16.

FIG. 20 is a fragmentary view partially in section of the apparatus ofFIG. 16 showing the conductive connection blade of FIG. 17 in place onthe fuel level sensor of FIG. 16.

FIG. 21 is a plan view of an alternative conductive connection bladeincorporating principles in accordance with the present invention.

FIG. 22 is a front view of an in-tank fuel module utilizing theconductive connection blade of FIG. 21.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the embodiment of FIG. 1, there is disclosed an in-tank fuel module10 adapted to be positioned in a fuel tank 9 associated with an internalcombustion engine. Though the main application of such an arrangement isfor a vehicle, the invention has application to other apparatus poweredby an internal combustion engine, such as a stationary or auxiliarypower unit, engine driven pump or electric generator.

The module 10 includes a flange 11 connecting the module to fuel tank 9.The module further includes a fuel reservoir 13, a fuel pump and motor18, a fuel filter housing 20 in which there is positioned a fuel filter19, a fuel pressure regulator 16, and an aspiration jet pump 21. Thesecomponents are connected by hoses 23 or 25. The module communicates fuelfrom the main tank 9 to the vehicle engine though the pump and motor 18to the filter housing 20 for delivery to the engine through an outletconnector 27.

Flange 11 supports an electrical receptacle 12. It receives power fromthe electrical system associated with the engine. The electrical systemincludes leads 8 a and 8 b that plug into receptacle 12. One lead, 8 a,represents the negative side of the battery of the electrical system andis considered representative of the system ground plane.

Fuel pump and motor 18 are supported in the reservoir 13. Power to themotor is supplied through electrical leads 17 a and 17 b connected toelectrical receptacle 12. Lead 17 a is connected to the negative lead 8a and is thus connected to the vehicle ground plane. Lead 17 b isconnected to the positive side of the battery through lead 8 b and isconsidered the “hot” or power lead.

The flange 11 and reservoir 13 are connected by a relatively slidableconnection to permit adjustment of the overall vertical extent of themodule. This slidable connection is not shown in FIG. 1, but is wellknown in the art. It permits the reservoir 13 to move toward or awayfrom flange 11 for association of the module with fuel tanks ofdifferent vertical height.

In the module illustrated, the fuel filter housing 20 and includedfilter 19 are connected to the flange 11. In other arrangements, thefilter housing may be connected to the reservoir 13.

As shown in FIG. 1, the filter housing 20 supports filter 19. Fuelenters the filter housing 20 from hose 23 that is connected to the pumpand motor 18. Pressurized fuel passes through the filter 19 and exitsthe filter through outlet connector 27 for delivery to the engine.

To prevent build-up of electrostatic charge and provide for itsdissipation, the lower portion 20 a of filter housing 20 may be made ofconductive polymeric material such as acetal (polyoxymethylene or POM)with a conductive filler. This conductive portion 20 a of the housing 20is connected to the vehicle ground plane at lead 17 a in a well knownmanner by an insulated metal wire (not shown). Of course, any other formof connection of the conductive portion 20 a to the electrical circuitground plane would be acceptable.

The reservoir 13 maintains a level of fuel for supply to the fuel pumpand motor 18. It includes an inlet defined by a screen 15 at the bottomof the reservoir maintained in spaced relation to the tank bottom. Fuelenters the inlet 15 from fuel tank 9, usually as a result of the headfrom the quantity of fuel in the tank 9. When the level of fuel in thefuel tank is low, jet aspiration pump 21 draws, or aspirates, fuel fromthe fuel tank 9 into the reservoir 13.

After fuel passes through filter 19, it can also exit the housing 20through hose 25 to pressure regulator 16. The regulator controlspressure of the fuel delivered to the engine through the outletconnector 27 by passing some fuel back to the reservoir 13 when thepressure exceeds a set amount. This is a supply side jet pump system.The invention here, is of course, applicable to systems with return sidejet pumps.

Jet aspiration pump 21 includes a body 29 that is hollow and defines arestricted orifice or venturi. The body also defines an inlet 31 open tothe fuel in the tank 9 at the reservoir inlet 15, and an outlet 33 opento the reservoir 13.

High pressure fuel in hose 25 is delivered through another hose 35 tothe jet orifice 32 which directs flow at high speed to the venture at 90degrees to the fuel path entering the inlet 19. The flowing fuelaspirates fuel from tank 9 into the inlet 31 of body 29. That fuel isdelivered to the reservoir 13 through outlet 33.

Aspirator jet pump 21 is made of conductive polymeric material such asacetal with carbon fibril, or other conductive filler or nylon with asuitable conductive filler. Such conductive material is used to form thebody 29 including the venturi and the portions of the body defininginlet 31 and outlet 33. The aspiration jet pump 21 is connected to theground plane using any suitable means, such as insulated metal wire.Alternatively, the entire reservoir 13 and other module components couldbe molded of conductive polymeric material to provide a dissipation pathfor any electrostatic charge that might be generated as a result of fuelflow in the aspiration jet pump 21.

FIG. 2 shows another form of an in-tank fuel module having a pluralityof separate components. The fuel module 110, includes a fuel levelsensor assembly 114, a fuel pressure regulator 116, a fuel pump andmotor 118 and a fuel filter housing 120 which houses a fuel filter (notshown).

An electrical plug or receptacle 112 is provided for connection to thevehicle electrical system. It includes at least a positive and anegative terminal. Positive and negative leads 117 a and 117 b connectto the pump motor 118. The ground terminal lead 117 a is electricallyconnected to a grounded portion of a vehicle or other chassis, which is,in turn connected to the negative terminal of the battery through lead108 a. Terminal lead 117 b is connected to the positive side of thecircuit through lead 108 b.

A conductive bracket 107 is provided that is attached to lead 117 a.

The fuel pressure regulator 116, the fuel pump and motor 118 and thefuel filter housing 120 all may be components or include elements in oron which accumulation of electrostatic charge may occur. To dissipatethe electrostatic charge from the fuel pressure regulator 116, the fuelpump 118 and the fuel filter housing 120. This embodiment usesconductive plastic or polymeric strands 122 to define an electricalconductor or electrically conductive path to the ground terminal lead117 a at the electrical plug 112. In FIG. 2, the strand or conductorextends from pressure regulator 116 to the fuel filter housing 120, andthen to the bracket 107. This single strand thus connects two componentsof the module to the electrical system ground plane. Another strand 122contacts the pump and motor 118 and connects to the first strand at theconnection to the filter housing 120. Bracket 107 and receptacle 112illustrate an effective arrangement to connect strands 122 to theelectrical circuit ground plane. Of course, metal wire could be used inplace of plastic strand 122 to provide the conductive path.

The illustrated polymeric strands are connected to the negative batteryterminal at receptacle 112. Bracket 107 includes a clip 124 to securethe strand 122 to the conductive bracket for a secure physical andelectrically conductive connection. Of course, a wire can be similarlyconnected.

The embodiment of an in-tank fuel module 110 of FIG. 2 includes a flange111 which as in the embodiment of FIG. 1 mounts the module to a fueltank. The flange connects to the top wall of the fuel tank and suspendsthe module 110 within the tank through an entry aperture closed by theflange 111. As in the earlier embodiment, the flange 111 and thereservoir generally designated 113, which carries the other componentsof the module are connected by a slidable connection to permitadjustment of the overall vertical extent of the module. The slidableconnection includes a pair of tubular vertical support tubes 140, one ofwhich is shown in FIG. 2 slidably received in vertical bores withinpillars 123 on the reservoir member 113. Each tube 140 is surrounded bya metal wire compression coil spring 142 that urges the flange 111 andreservoir 113 toward the fully extended or elongated condition. When,for example, the reservoir section 113 of a fuel module 110 in anyinstallation contacts the bottom of its associated tank, the springs 142are compressed to move the flange 111 into its sealed connection withthe top wall of the fuel tank.

The flange 111 is usually molded of non-conductive polymeric material asacetal. The support tubes 140 are metal and conductive. The springs 142are, of course, also conductive. Thus, the support tubes and springs area potential location for the build-up of electrostatic charge.

FIGS. 3 and 4 illustrate an arrangement for dissipation of electrostaticcharge from the metal support tubes 140 and a metal compression coilsprings 142.

A flange 111 is illustrated. FIG. 3 shows the top 144, of the flangeexternal to the fuel tank. FIG. 4 shows the underside or bottom surface146 that faces downward, or into the tank, when the module is mounted toa tank.

Referring to FIG. 4, the bottom 146 of flange 111 includes a pair oftube posts 148 are molded into the flange. Each of these posts includean internal cylindrical surface 150 defining a bore to receive a tube140. The outside diameter of each tube 140 is such that it isfrictionally engaged within cylindrical surface 150 of one of the posts148.

The flange 111 supports a fuel supply port member 152 which includesinternal stem 154. It is arranged to receive fuel from module 110through a flexible hose within the tank. Such a hose is illustrated at115 in FIG. 2. The hose is conductive and usually formed of a polymericmaterial filled with conductive material. Port 152 connects to a fueldelivery hose at its stem 153 outside of the fuel tank. The hoseconnected to stem 153 delivers fuel to the associated consumptioncomponent. The hose is usually made of conductive polymeric material, orincludes a conductive polymeric layer in contact with stem 153.

The flange 111 includes a conductive web 156 in the form of anovermolded polymeric band. The web or band 156 includes ends 158 thatare exposed within the internal cylindrical surface 150 of tube posts148 and a branch 160 in contact with fuel supply port 152. The ends 158contact the outer surface of tubes 140 and define a seat 151 to contactthe end of spring 142. As illustrated, ends 158 may also include acentral pin 149 positioned within the bore defined by cylindricalsurface 148. The outer surface of each pin 149 contacts the inner boreof a tube 14 to provide an additional conductive path from the tubes tothe web 156.

The web 156 provides a conductive path from posts 148 to the supply port152. Its ends contact the metal support tubes 140 and connect the tubes140 and metal springs 142 to the conductive supply port 152. Aconductive path is thus provided to dissipate any electrostatic chargethat could otherwise accumulate on the support tubes 140 or springs 142to port 152 and to its associated conductive hose 115 forming part ofthe fuel module.

The web 156 is an overmolded piece formed of conductive polymericmaterial that is preferably the same polymer as the non-conductiveflange 111. As best seen in FIG. 3, the web includes upstanding feet or“stand offs” 157 that support it in its appropriate position within themold for injection molding of flange 111. Stabilization of its positionis important to the molding process. Since it is made of the samepolymer as the flange 111, the material of the web 156 and the flange111 form a fluid tight relationship during the overmolding process.

Turning now to FIGS. 5 and 6, a fuel level sensor assembly 414 is shown.It includes a conductive base or conductive card body 415 mounted to anin-tank fuel module. For example, as in the configuration of FIG. 2,fuel sensor assembly 114 is mounted to the fuel filter housing 120.Often the card body or base 415 is mounted on a molded vertical pillarextending from the top of the filter housing.

The conductive card body 415 of FIGS. 5 and 6 includes a card retentionsection 417 with locking fingers 416. It also includes an integrallymolded socket 418 defining a horizontally extending cylindrical bearingsurface 419 best seen in FIG. 6. The conductive card body 415 is made ofa conductive polymer, such as acetal filled with conductive materialsuch as carbon fibrils.

A resister card 448 which forms a part of a circuit associated with thefuel level indicator is supported on card body 415. It is held in placeby fingers 416. The card 448 is made of non-conductive material such asa polymer or a ceramic. As is usual, and well known, the circuit isconnected to the battery circuit and therefore provides a path to thenegative battery terminal or ground plane.

The resister card 448 includes a pair of separate traces 450 thattypically extend in an a parallel pattern that is arc shaped.

An insulated wire 500 enters the module through receptacle 112 of FIG.2, and connects to a first pattern of traces 450 at an end of theresister card 448. A second insulated wire 501 connects between thereceptacle 112 the other pattern of traces 450 on card 448. Wire 501 issuitably connected to the negative battery terminal ground plane of thesystem through the receptacle 112. Wire 501 could, however, be connectedto the ground plane. Either wire could be so connected through any othersuitable path, such as a wire connected to the negative terminal 17 a ofpump motor 18 in the embodiment of FIG. 1.

An elongate metallic float arm 440 has one end portion 441 bent at 90degrees to its length. That end is supported on a contact carrier 444.An opposite end portion is also bent at 90 degrees to its length andsupports buoyant float 442.

A best illustrated in FIGS. 9-11, contact carrier 444 is a moldedpolymeric component with an elongated body with finger 421 to receiveand secure the elongated portion of the metallic float arm 440. Contactcarrier 444 has a protrusion or cylindrical shaft like element 462 atone end that defines a bore 464 in which is disposed the end portion 441of float arm 440. Protrusion 462 defines a cylindrical bearing surface463. Surface 463 is pivotally supported upon bearing surface 419 ofsocket 418 on card body 415.

As the level of the fuel changes, the float 442 moves up and downcausing the float arm 440 and contact carrier 444 to pivot in socket418. As the float arm 440 pivots, contacts 458 on contact member 446move along the arc shaped conductive traces 450 of the resistor card448, which then alters the characteristics of the circuit and thus thesignal sent to the fuel level indicator (not shown).

The contact member 446 of the present invention has a conductive finger452 that contacts float arm 440. As illustrated, the conductive finger452 is an extension of the contact member 446. It could, however, takethe form of a separate conductive bracket (not shown) electricallyconnecting the float arm to the contact member, a metallic wire (notshown) electrically connecting the float arm to the contact member or aconductive plastic strand (not shown) connecting the float arm to thecontact member. While all the above listed conductive portions areeffective in electrically connecting the float arm to the contactmember, the preferred form is the conductive finger extension of thecontact member 446 illustrated in the drawings. By using the finger onthe contact member 446, no additional parts are required for theelectrical connection. This approach saves assembly time and money, andeliminates some failure modes, such as a potentially loose ordisconnected wire.

FIGS. 7 and 8 illustrate a contact member 446 prior to installation ontoa contact carrier 444. The contact member 446 has a main plate 454defining two small apertures 456 for attaching cylindrical contacts 454.The cylindrical contacts 458 are adapted to contact the traces 450 ofthe resistor card 448. The circuit across the separate traces 450 iscompleted through contact member 446. The main plate 454 also defines alarge aperture 460 adapted for attaching the contact member 446 to thewiper retainer 444. Extending from the end of the main plate 454 is theconductive finger 452. The terminal end of the conductive finger 452 isadapted to contact the float arm 440 to form an electrical path todischarge any electrostatic charge collected in the float arm 440 to thecircuit defined by the traces 450 and wires 500 and 501. The contactmember 446 depicted here is one example of such a component. Variousother contact member configurations and methods of attachment to thecontact retainer may be employed without deviating from the presentinvention.

FIG. 11 illustrates the contact member 446, as illustrated in FIGS. 7and 8, attached to the contact carrier 444, as illustrated in FIGS. 9and 10. FIG. 11 further illustrates end portion 441 of the float arm 440extending through the bore 464 of the contact retainer 444.

The conductive finger 452 of the contact member 446 is in contact withthe float arm 440. The conductive finger 452 creates an electrical pathfor any electrostatic charge in the wiper arm 440 to travel to ground ina safe manner. The electrostatic charge in the float arm 440 travelsfrom the float arm 440, through the conductive finger 454, to the mainplate 454 of the contact member 446, to contacts 458, into the traces450 of resister card 448 and to ground via the wires 500 and 501attached to the traces on resister card 448.

It is contemplated that, alternatively, the contact carrier itself canbe conductive. The conductive contact carrier can be made conductive bymixing a base non-conductive polymer, such as acetal, with conductivefiller additive, such as carbon fiber or carbon fibrils. It would thenconnect the metal float arm 440 to ground through the contact member 446and contacts 458 which electrically contact the traces 450 of theresister card 448.

Turning now to the embodiments illustrated in FIG. 12-14, there isillustrated an alternative arrangement for dissipation of anyelectrostatic charge that might otherwise build-up on the float wire orarm 440.

The arrangement illustrated includes a card body 415, a contact carrier444, and a metallic float arm 440. The card body 415 holds a resistercard as in the previous embodiment. It also includes socket 418 thatdefines a cylindrical surface 419. It further includes a conical portion422 that defines an aperture 423. Extending in a direction oppositeconical portion 422 are resilient latch members 425. In this embodiment,a cap 427 is releasably attached over the card body 415 to cover theresistor card and contacts.

Contact carrier 444 is formed as described in the previous embodiment.It includes a protrusion 462 defining a bore 464 that receives the end441 of float arm 440. Protrusion 462 defines a cylindrical surface 463that pivotally mounts the contact carrier 444 upon card body 415. Notethat latches 425 capture the contact carrier 415 and releasably retainit in its pivotally supported relationship to the cylindrical bearingsurface 419.

The metal float arm or wire 440 is shaped like the arm in the previousembodiment. It has a first end 441 bent 90 degrees to the length of thearm received in contact carrier 444. End portion 441 extends through thebore 464 in protrusion 462 of contact carrier 444 and is piloted inaperture 423 of conical portion 422 of card body 415. A tip 443 of floatarm extends beyond the surface of conical portion.

As generally annular dissipation cap 470, shown in plan view in FIG. 13,is connected to the open end of conical portion 422 of card body 415. Itis made of non-corrosive or plated metal and includes an annular body471 with gripping teeth 472 that adhere the cap to the open end ofconical portion 422. It also is provided with a resilient contact finger474 that includes a contact surface 475 in abutting contact with tip 443of float arm 440. The dissipation cap is pressed onto the end of conicalportion 422 sufficiently to flex finger 474. The restoring force of thefinger thereby urges surface 475 into contact with tip 443 of metalfloat arm 440.

The cap 470 also a terminal tab 476. A wire 517 is connected to the taband leads to the ground plane or negative terminal of the battery. Itconnects within, the fuel module, to the negative lead 17 a by anyappropriate connection. The wire includes a push-on connector clip 478that slips over tab 476 and frictionally adheres to it. The connectionbetween the wire 517 and the tab can take any suitable form. They could,for example, be molded together. Also, a conductive polymeric strandcould be used as previously described in connection with FIG. 2. Notethat use of wire 517 contemplates that the card body 415 is made ofnon-conductive polymeric material. If it were, for example, made ofconductive polymeric material such a metal with a filler of carbonfibrils, the wire 517 would not be necessary. The card body 415 would beconnected to the negative side of the battery elsewhere, and thedissipation cap 470 would provide a dissipative path from float arm 440to the conical portions 422 of protrusion 462.

FIG. 14 shows a modified form of dissipation cap 470 a. It is also madeof metal. It includes an annular body 471 a and gripping teeth 472. Itis intended to be placed on the conical portion 463 of a protrusion 462of a cord body 415 as in the embodiment of FIGS. 12 and 13.

Dissipation cap 470 a defines a sleeve 480 that resides within theaperture 423 of conical portion 463. It defines an inner bearing surface482 for contact with the outer surface of end 441 of metallic float arm440. The contact between the outer surface of the arm 440 with the innerbearing surface 482 is sufficient to provide a dissipation path to thedissipation cap 470 a.

The dissipation caps 470 and 470 a illustrated in FIGS. 12-14 areexemplary of an arrangement to provide a dissipative path from the metalfloat wire 440 to the card body 415. Numerous alternative arrangementsare contemplated. For example, the cap 470 or 470 a could be made ofconductive polymeric material such as acetal filled with conductivematerial. Also, it is contemplated that the resilient contact finger 474could be arranged to contact the outer surface of end 441 of metal floatarm 440 rather then tip 443. The main principle involved is that theconductive dissipative path extends from the float wire 440 to the cardbody 415 through a contact element such as dissipative cap 470.

Turning now to the embodiments of FIGS. 15-20, there are illustratedarrangements for providing a dissipative path from a card body to groundby connection to the wire or lead 500 or 501 associated with the fuelsending unit. Referring to FIGS. 15 and 16, a fuel level sensor assembly614 is illustrated, such as the fuel sensor assembly 114 of theembodiment of FIG. 2 or 5-11. It includes a base or card body 615mounted to an in-tank fuel module. For example, as in the configurationof FIG. 2, fuel sensor assembly 114 is mounted to the fuel filterhousing 120. Often the card body or base 615 is mounted on a moldedvertical pillar extending from the top of the filter housing.

The card body 615 of FIGS. 15 and 16 includes a card retention section617 with locking fingers 616, best seen in FIG. 16. It also includes anintegrally molded socket 618 defining a horizontally extendingcylindrical bearing surface 619 best seen in FIG. 16. The card body 615is made of a conductive polymer, such as acetal filled with conductivematerial such as carbon fibrils. Alternatively, the conductive card body415 can be made conductive by molding or applying a layer of conductivematerial, such as a conductive polymer, to at least one surface of anotherwise non-conductive card body.

A resister card 648 which forms a part of a circuit associated with thefuel level indicator is supported on card body 615. It is held in placeby fingers 616. The card 648 is made of non-conductive material such asa polymer or a ceramic. As is usual, and well known, the fuel levelsensing circuit is connected to the battery of the vehicle and thereforeprovides a path to the negative battery terminal or ground plane.

The resister card 648 includes a pair of separate traces 650 thattypically extend in an a parallel pattern that is arc shaped.

An insulated wire 500 enters the module through receptacle 112 of FIG.2, and is soldered to a first pattern of traces 650 near one end of theresister card 648 at terminal connection 680. A second insulated wire501 connects between the receptacle 112 the other pattern of traces 650on card 648. Wire 501 is soldered to the second trace pattern atterminal connection 681. Wire 501 is suitably connected to the negativebattery terminal ground plane of the system through the receptacle 112shown in FIG. 2. Wire 500 could, however, be connected to the groundplane. Either wire could be so connected through any other suitablepath, such as a wire connected to the negative terminal 17 a of pumpmotor 18 in the embodiment of FIG. 1.

The arrangement of FIGS. 15-20, as in the embodiment of FIGS. 5-11,includes an elongate metallic float arm 640 supported on a contactcarrier 644. An opposite end of the arm 640 supports a buoyant float,such as the float 442 of the embodiment of FIGS. 5-11.

A best illustrated in connection with the embodiment of FIGS. 9-11,contact carrier 644 has an elongated body that receives and secures themetallic float arm 640. Contact carrier 644 is pivotally supported uponbearing surface 619 of socket 618 on card body 615. It carries contactas described in connection with the embodiment of FIGS. 5-11 thatcontact the traces 650 on resistor card 648 to define a sensed signalfor indication of fuel level.

As the level of the fuel changes, the float moves up and down causingthe float arm 640 and contact carrier 644 to pivot. As the float arm 640pivots, contact carrier 644 moves the contacts along the arc shapedconductive traces 650 of the resistor card 648, and alters thecharacteristics of the circuit and thus the signal sent to the fuellevel indicator (not shown).

Resistor card 648 of the embodiment of FIGS. 15 and 16 includes aseparate conductive path or trace 682 best illustrated in FIG. 16 thatconnects to terminal connection 681. It also extends to exposedconductive surface 684 located under a locking finger 616. Finger 616makes conductive contact with surface 684.

The above arrangement provides a conductive path or at least a pathsufficient for dissipation of electrostatic charge from card body 615 tothe ground plane or negative battery terminal. Any charge that mightaccumulate on conductive card body 615, and if the metal dissipationcaps of the embodiment of FIGS. 12-14 are employed, the float arm 640,travels through locking finger 616 to conductive surface 684 and alongseparate conductive trace 682 to the junction with wire 501 at terminalconnection 681. The conductive trace 682 could, of course, connectanywhere along trace 650. However, by connecting directly to connector681 any electrostatic charge dissipated along this path goes directly towire 501 and does not involve traces 650 on resistor card 648. This waythere is no potential for interference or undesirable input to thesending circuit which involves the resistor traces 650 and contactscarried by contact carrier 644.

FIGS. 15-20 illustrate another mechanism for creating a dissipative pathto the wires 500 and 501 of the fuel level sensor assembly 614. In theembodiment illustrated, this mechanism provides a ground path from thecard body to one or both wires 500 and 501.

As seen in FIG. 15, in the embodiment illustrated, card body 615includes support brackets 685 defining spaced wire retention jaws 686.The jaws are spaced apart a distance slightly smaller than the outerdiameter of insulated wires 500 and 501 such that the wires arereleasably retained between the insulated outer surface of the wire andthe jaws 686 of bracket 685. This relationship holds wires 500 and 501in place. Support brackets 685 are not a part of the invention and neednot be employed to enjoy the benefit of the disclosed electrostaticdissipative arrangement.

As best seen in FIG. 16, card body 615 includes grounding brackets 687one of which is associated with each insulated wire 500 and 501.

Referring to FIGS. 19 and 20 grounding brackets 687 define a bladereceptacle 688 forming slot generally surrounding each wire 500, 501.The slots of blade receptacle 688 include spaced walls 689.

A conductive connection blade 690, shown in detail in FIGS. 17 and 18,is disposed within each slot between walls 689. As best seen in FIG. 17,connection blade 690 is a generally U-shaped member having legs 691 anda cross element 692. The legs include inner, facing knife edges 693spaced apart a distance smaller than the diameter of the uninsulatedconductor 503 of insulated wire 500 and 501. The conductor 503, asillustrated in FIGS. 19 and 20, is made of a plurality of strands 504covered by insulation 505.

The connector blade 690 includes transverse points 697 that are intendedto imbed into the slot defining surfaces or walls 689 of groundingbrackets 687 to hold the connecting blade 690 in place. As illustratedin FIG. 18, the connecting blade is narrow and sized to slide into theslots formed in blade receptacle 688.

To complete a conductive or electrostatic dissipative connection betweenone or more of the wires 500 and 501, a conductive connection blade 690is inserted into the slot between spaced walls 689. The knife edges 693on the inner surface of legs 691 cut through the insulation 505 and makeconductive contact with the uninsulated conductor 503. The points 697imbed into wall surfaces 689 to hold the connection blade in place.Notably, it is only necessary to connect one of the wires 500 or 501 andpreferably the wire 501 to the card body using a connection blade 690.The slot associated with wire 500 can be left empty.

Blade 690 is made of conductive material. It could be made of metal,such as non-corrosive metal or plated metal. It could also be made of aconductive polymer, such as acetal with carbon fibrils or metallicfiller such as finely ground stainless steel particles.

It should be noted that the grounding brackets 687, and conductiveconnection blade 690 can be utilized to provide a dissipative connectionbetween any component and an insulated wire or conductive strand. Itcould, for example, be employed to connect strand 122, or an insulatedwire to various module components in the in-tank fuel module illustratedin FIG. 2. In this regard, the grounding bracket 687 and blade 690 wouldreplace clip 124. Such component may be a part of an in-tank fuelmodule, or any other device where a dissipative connection is desired.

FIG. 21 shows another embodiment of a conductive connection blade. Theblade 790 is similar to the blade 690 but includes a plurality of barbs794 extending from the knife edges 793. The blade 790 is a generallyU-shaped member having legs 791 and a cross element 792. The legsinclude inner, facing knife edges 793 spaced apart a distance smallerthan the diameter of the uninsulated conductor of the insulated wire.The blade 790 includes barbs 794 extending inwardly and upwardlyallowing the knife edges 793 to slide easily over the insulatedconductor when cutting the insulation but providing resistance for theknife edges 793 from separating from the conductor once the knife edgesmade contact with the uninsulated conductor. The blade 790 can be madeof metal, such as non-corrosive metal or plated metal, or a conductivepolymer, such as acetal with carbon fibrils or metallic fillers such asfinely ground stainless steel particles.

The blade 790 can be utilized as part of a conductive connection from atleast one conductive fuel module component, which is otherwise isolatedfrom the ground plane, to a ground plane of a vehicle in order todissipate any electrostatic charge that might have generated in or onthe conductive fuel module component. A conductive plastic stand 122, ofthe type previously disclosed, can be used to form the electricalconnection between the conductive fuel module component and the blade790. Alternatively, a metal wire can be used to form the electricalconnection between the conductive fuel module component and the blade790.

FIG. 22 illustrates an in-tank fuel module 710 having a plurality ofseparate components. The fuel module 710, includes a flange 711 whichmounts the module to a fuel tank. The flange is connected to the topwall of the fuel tank and suspends the module within the tank. Theflange 711 and a reservoir 713 carry the other components of the modulewhich are connected by a slidable connection to permit adjustment of theoverall vertical extent of the module. The slidable connection includesa pair of tubular vertical tubes 740. Each tube is surrounded by a metalwire compression coil spring 742 that urges the flange and reservoirtoward the fully extended or elongated condition. The fuel module 710further includes a fuel level sensor assembly 714, a fuel pressureregulator 716, a fuel pump and motor 718 and a fuel filter housing 720which houses a fuel filter (not shown). An electrical plug or receptacle712 is provided for connection to the vehicle electrical system. Itincludes at least a positive and a negative terminal. Positive andnegative leads 717 a and 717 b are connected to the pump motor 718. Uponassembling the fuel module 710 to a vehicle, the lead 717 a iselectrically connected to a grounded portion of the vehicle or otherchassis components.

A plurality of plastic strands 122 electrically connect the blade 790 tothe conductive fuel module components. A strand 122 a electricallyconnect the fuel level sensor assembly 714, including its conductivefloat arm, to the blade 790. Another strand 122 b electrically connectthe fuel pressure regulator 716 to the blade 790. A third strand 122 celectrically connect the fuel filter housing 720 to the blade 790. Afourth strand 122 d electrically connect the tube 740 and the spring 142to the blade 790. To complete a conductive or electrostatic dissipationconnection between the conductive fuel module components and a groundplane, the blade 790 is slid around the lead 717 a with the knife edges793 cutting through the insulation of the lead 717 a and making contactwith the uninsulated conductor of the lead 717 a. Once the knife edges793 is in contact with the uninsulated conductor, the barbs 794 of theknife edges prevent the blade 790 from separating from the lead 717 a.

Various features of the present invention have been described withreference to the above embodiments. It should be understood thatmodification may be made without departing from the spirit and scope ofthe invention.

1. A fuel level sensor assembly of a fuel module comprising: aconductive card body; and a resister card supported on said conductivecard body, said resister card includes a conductive trace in conductivecontact with said conductive card body and adapted to be placed inconductive contact with a ground plane to provide a path for dissipationof electrostatic charge from said card body to the ground plane.
 2. Thefuel level sensor assembly of claim 1 wherein said conductive card bodyis in conductive contact with a conductive fuel module component.
 3. Thefuel level sensor assembly of claim 2 wherein said conductive fuelmodule component is a conductive float arm pivotally supported on saidcard body.
 4. The fuel level sensor assembly of claim 3 furthercomprises a contact member attached to said float arm, said resistercard further includes a second conductive trace and a third conductivetrace, said conductive trace and said third conductive trace are inconductive contact with said contact member.
 5. The fuel level sensorassembly of claim 4 further comprises a non-conductive contact carrierattaching said contact member to said float arm.
 6. The fuel levelsensor assembly of claim 5 wherein said contact carrier is made of anon-conductive polymeric material.
 7. The fuel level sensor assembly ofclaim 4 wherein said contact member includes two contacts, said secondconductive trace contacts one of said contacts of said contact member,said third conductive trace contacts other of said contacts of saidcontact member.
 8. The fuel level sensor assembly of claim 4 whereinsaid second conductive trace and said third conductive trace are arcshaped.
 9. The fuel sensor assembly of claim 4 wherein said secondconductive trace and said third conductive trace are adapted to beplaced in the electrical circuit of the fuel level sensor.
 10. The fuelsensor assembly of claim 4 wherein said second conductive trace and saidthird conductive trace are conductively insolated from each other onsaid resister card.
 11. The fuel level sensor assembly of claim 2further comprises a conductive float arm and a contact member attachedto said float arm, said resister card further includes a secondconductive trace and a third conductive trace, said second conductivetrace and said third conductive trace are in conductive contact withsaid contact member.
 12. The fuel sensor assembly of claim 11 where insaid second conductive trace and said third conductive trace are adaptedto be placed in the electrical circuit of the fuel level sensor.
 13. Thefuel sensor assembly of claim 11 wherein said second conductive traceand said third conductive trace are conductively insolated from eachother on said resister card.
 14. The fuel sensor assembly of claim 1wherein said card body is made of a conductive polymer.
 15. The fuelsensor assembly of claim 14 said conductive polymer is acetal filledwith a conductive material.
 16. The fuel sensor assembly of claim 1wherein said card body includes a card retention section, said cardretention section contacts said conductive trace.
 17. The fuel sensorassembly of claim 1 wherein said resister card is non-conductive.